It is known in the solenoid art to provide solenoids having spring biased pole pieces to overcome tolerance problems in valves. An example of such a prior art solenoid is disclosed in U.S. Pat. No. 3,538,954. A disadvantage of such prior art solenoids is that they are not self-contained, and the parts thereof must be disassembled and reassembled individually when maintenance and repair operations are required. A further disadvantage of such prior art solenoids is that they are noisy, because of misalignment between the moving parts thereof. In order to overcome the disadvantages of the aforementioned solenoids, it was proposed to provide a self-contained solenoid which could be inserted and removed from a valve construction as a complete unit, so as to reduce lost parts, maintenance, repair time and the cost of the same. The self-contained solenoid was provided with a floating tubular guide member for maintaining alignment of the solenoid plunger and a spring biased movable pole piece. However, a disadvantage for low-wattage solenoids of the last described tubular guide member is that the transfer of the magnetic flux is inefficient from the solenoid coil into the magnetic components, namely, the frame, the pole piece and the armature. In order to increase the efficiency of the transfer of magnetic flux, the thin guide tube was used with magnetic bushings and non-magnetics bushing for guiding the pole piece and the armature. An example of a prior art solenoid provided with a thin guide tube for the pole piece and armature is disclosed and described in U.S. Pat. No. 4,100,519.